Chromium (VI), also known as hexavalent chromium, is the second most stable oxidation state of chromium. Rarely occurring naturally, most chromium (VI) compounds are manufactured (products or by-products). Chromium (VI) can be reduced to the more stable chromium (III) in the presence of reducing agents (e.g. iron) or oxidizable organic matter (OSHA, 2006). Selected chemical and physical propert...

Composite hydrogels were prepared that consisted of quasi-colloidal layered double hydroxide (LDH) nanoparticles and agarose via the electrophoretic method, starting from three different agarose concentrations of 0.5, 1, and 2 wt/v%. The composite hydrogel was identified to have a uniform distribution of LDH nanoparticles in agarose matrix. Microscopic studies revealed that the composite hydrog...

The use of cellulose-containing agricultural by-products modified with the cross-linking reagent dimethyloldihydroxyethylene urea (DMDHEU) and the quaternary amine, choline chloride, as anion exchange resins, has not been reported. The objective of the present study was to convert the readily available by-products, soybean hulls, sugarcane bagasse and corn stover to functional anion exchange re...

Currently, heavy metals pollution is significantly becoming a global concern as it causes severe toxicity towards human health and the environmental condition. Intensive efforts to develop highly sensitive, rapid, simple assay assess toxic effects of in aquatic bodies have been done. An emerging tool solve this matter by using microorganisms one them yeast. In study, simple, cost-efficient Bake...

BEIs: Threshold limit values for chemical substances and physical agents biological exposure indices. Cincinnati, OH: American Conference of Governmental Industrial Hygienists. *ACGIH. 1999b. Strontium chromate. 1999 TLVs and BEIs: Threshold limit values for chemical substances and physical agents biological exposure indices. Cincinnati, OH: American Conference of Governmental Industrial Hygien...

A 46-year-old man who had worked as a bumper spray painter in an automobile body shop for 15 years developed lung cancer. The patient was a nonsmoker with no family history of lung cancer. To determine whether the cancer was related to his work environment, we assessed the level of exposure to carcinogens during spray painting, sanding, and heat treatment. The results showed that spray painting...

The surface characteristics of an aluminium alloy treated with a commercial chromate pretreatment have been studied by SAM, EDX and XPS. XPS indicates that the chromium is present in the conversion coating as both Cr(III) and Cr(VI) species, and that other components are present at the conversion coating surface, some in a reduced form. The deposition of the chromate layer is compromised by the...

BACKGROUND Chronic inflammation is implicated in the development of several human cancers, including lung cancer. Certain particulate hexavalent chromium [Cr(VI)] compounds are well-documented human respiratory carcinogens that release genotoxic soluble chromate and are associated with fibrosis, fibrosarcomas, adenocarcinomas, and squamous cell carcinomas of the lung. Despite this, little is kn...

Most bacteria contain soluble quinone-reducing flavoenzymes. However, no biological benefit for this activity has previously been demonstrated. ChrR of Pseudomonas putida is one such enzyme that has also been characterized as a chromate reductase; yet we propose that it is the quinone-reducing activity of ChrR that has the greatest biological significance. ChrR reduces quinones by simultaneous ...

Surfactant-modified minerals have been widely used for the sorption of anionic and non-polar organic contaminants. This paper investigates the regeneration of various hexadecyltrimethylammoniun bromide (HDTMA)-modified natural minerals saturated with chromate anions using different solutions for the extraction of chromate that has been sorbed at optimum conditions. The examined minerals include...